Head for handling electrical components

ABSTRACT

A pick-up head especially for use in a machine for placing electrical components on a substrate comprises a tool holder mounted for movement, conveniently by a lead screw driven by a motor, between a plurality of datum positions and further positions remote therefrom, having means for interchangeably mounting a pick-up tool with a datum face of the tool located at a predetermined position relative to the tool holder. The head further comprises a plurality of orienting jaws mounted for movement towards and away from a component carried on the datum face of a tool on the tool holder when the holder is in one of the datum positions whereby the jaws can engage the component to orient the component. The jaws have a plurality of spaced sets of cooperating datum faces disposed generally transversely to the plane of the datum face of the tool in the holder, each set of datum faces being disposed so as to be capable of orienting a component carried by a tool mounted on the tool holder when the holder is at a corresponding one of said datum positions. A machine including the pick-up head comprises a tool support for supporting a plurality of tools and the machine is arranged so that tools carried by the pick-up head may be interchanged with tools in the tool support dependent upon the components which are to be handled. A wide range of components sizes can be handled using the single pick-up head.

FIELD OF THE INVENTION

This invention relates to heads for handling electrical components, forexample so-called "chips", flatpacks, S.O. style transistors, leadlesschip carriers and the like, and to machines for handling electricalcomponents comprising such heads.

BACKGROUND OF THE INVENTION

It is necessary to handle electrical components for a variety ofpurposes in modern technology. One major area in which many componentshave to be handled is the application of components to substrates, forexample printed circuit boards, in the assembly of electronic circuitry.In the handling of electronic components, specially in placing variouscomponents on printed circuit boards, it is essential that thecomponents be positioned precisely at a desired location and in adesired orientation. Many machines have been proposed for accuratelyplacing components on substrates. Some of these previously knownmachines have included so-called pick-up heads by which components arepicked up from a component supply and placed in a desired position andorientation on a suitable substrate. U.S. Pat. Nos. 4,135,630 and4,290,732 both describe machines for picking up electrical componentsand placing them at desired positions and orientations on a suitablesubstrate. The pick-up heads of the machines described in each of theseU.S. patent specifications have a vacuum or suction tool by whichcomponents are held on the pick-up head and so-called pawls or fingersby which the components are positioned accurately in correct orientationon the tool. Machines of this type are capable of very precisepositioning of components of appropriate size. However, it is frequentlynecessary to position a number of components of widely varying sizes ona single substrate. By way of example components to be placed on asingle board may have sides ranging from 1.25 mm to 31.5 mm in lengthand may be up to 6.5 mm in thickness. The heretofore known machines, forexample of the type described in the aforementioned U.S. patentspecifications, are capable of satisfactorily handling a small range ofsizes of components; however, in order to accommodate components of thesize variation which it is often necessary to position on substrates,sufficient accuracy and reliability has not been achieved with a singlepick-up head without manually adjusting or changing the pawls orfingers, or alternatively providing the components in an alreadyorientated manner. This latter system demands extreme accuracy indelivering components to the pick-up head which requires a componentfeed means which is dimensionally accurate to very close tolerances andhence which is very expensive--known component feed systems providecomponents in pockets of reeled tapes or so-called "sticks" in both ofwhich cases it is difficult to ensure that the components supplied areoriented in the component supply sufficiently accurately. In addition,if, in order to achieve sufficiently precise positioning, the componentfeed is relied on to give the necessary accuracy, there is aconsiderable period (from picking the components from the componentsupply to finally placing the components on the substrata) during whichthe components may be disturbed on the pick-up head thereby losing theorientation and precise positioning of the components. Changing of thepawls or fingers on pick-up heads of the type shown in theaforementioned U.S. patent specifications would be a most inconvenientand time-consuming operation and, furthermore, it is difficult to ensurethat the replacement pawls or fingers are sufficiently precisely mountedon the pick-up head--great care is required to achieve the necessaryprecision. Accordingly, where components of a wide variety of dimensionshave been called for on a single substrate it has been customary topresent the substrate to a plurality of pick-up heads each capable ofhandling components of different and complementary size ranges.Precision pick-up heads are expensive and a plurality of heads is,furthermore, wasteful of space.

OBJECTS OF THE INVENTION

It is one of the various objects of the present invention to provide animproved head for handling electrical components and orienting thecomponents, which can deal with a bigger range of sizes of componentsthan has hitherto been conveniently possible with the a head comprisingorientation pawls or fingers.

Another object of the present invention is that of providing a machinefor handling electrical components including a head capable of handlingcomponents having a wider size range than hitherto conveniently possiblewith a single head.

SUMMARY OF THE INVENTION

The above and other objects are achieved by providing a head forhandling electrical components comprising a tool holder, means formoving the holder between a plurality of datum positions and furtherpositions remote therefrom, the holder having means for interchangeablymounting a tool with a datum face thereof positioned at a predeterminedposition relative to the tool holder, the head further comprising aplurality of orienting jaws mounted for movement towards and away from acomponent carried by and abutting the datum face of a tool mounted onthe tool holder when the holder is in one of the datum positions wherebyto engage and orient a component carried by the tool, the jaws having aplurality of spaced sets of cooperating datum faces generally transverseto the plane of the datum face of a tool in the holder, each set ofdatum faces of the jaws being so disposed as to be capable of orientinga component carried by a tool mounted on the tool holder when the holderis at a corresponding one of said datum positions.

With a head having several sets of orienting jaws, it is possible tohandle a wider range of components than with previously known heads.Suitably the tools carried by the holder can be interchanged so that theholder mounts a tool most appropriate for the compoent to be carried bythe tool. Preferably the tool holder of a head according to theinvention has a socket in which a shank portion of a tool can bereceived to mount the tool on the holder in a located position, the toolholder being conveniently provided with retaining means to retain theshank of the tool in the socket.

A machine for handling electrical components comprising such a head withinterchangeable tools also comprises means facilitating interchanging ofthe tools. Such a machine comprises a tool support for supporting aplurality of tools and means for relatively moving the head and toolsupport whereby to mount a preselected tool carried by the tool supporton the tool holder. Provision of such a tool support enables a machinefor handling electrical components and, for example, placing thecomponents in predetermined positions on substrates, to operate withoutany intervention during the operative cycle from the operator to handlea wide variety of components.

BRIEF DESCRIPTION OF THE DRAWINGS

There now follows a detailed description to be read with reference tothe accompanying drawings, of a component placing machine having apick-up head embodying the invention. It will be realized that thismachine has been selected for description to illustrate the invention byway of example.

In the accompanying drawings

FIG. 1 is a perspective view of the component placing machine;

FIG. 2 is a view in side elevation of the machine embodying theinvention;

FIG. 3 is a view in section showing part of the pick-up head;

FIG. 4 is a plan view of part of a carriage of the machine showing atool support thereof;

FIG. 5 is a front view showing the tool support of the FIG. 4;

FIG. 6 is a view in front elevation of part of the machine showing twinpick-up heads of the machine with a cover partly broken away;

FIG. 7 is a diagrammatic plan view showing the relationship of jaws ofthe pick-up head when in a closed condition orienting a component; and

FIGS. 8 and 9 are perspective views of jaws of the pick-up head.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A component placing machine for handling electrical components, forexample so-called "chips", and placing them in predetermined positionson a suitable substrate, for example a printed circuit board or boards,embodying the invention, is shown in FIG. 1. The component placingmachine comprises a frame 10 including a bridge member 12 on which aremounted twin pick-up heads 14. Two carriages 16 are mounted for movementalong parallel paths beneath the bridge member 12, each carriage 16being associated with one of the pick-up heads 14; on each of thecarriages 16 a tool support 18 for supporting a plurality of tools 20for supply to the associated pick-up head, is disposed. Between the twocarriages is mounted a substrate support 22 on which substrates 24, forexample printed circuit boards, may be located for placement ofelectrical components thereon. The machine further comprises means (tobe described in greater detail hereinafter) for relatively moving thepick-up heads 14 and tool supports 18 whereby to mount a preselected oneof the tools 20 carried by the tool support 18 on a tool holder 26 (seeFIG. 3) of the pick-up heads 14.

The pick-up heads 14 are mounted for rotation about spaced vertical axesin bearing 28 carried by support brackets 30 of a head support member32. The pick-up heads 14 are substantially identical in construction andtherefore only one of the heads will be described in detail hereinafter.

This pick-up head comprises a body member 34 which is supported forrotation in the bearings 28. The body member 34 is hollow and a carrier36 to which is secured a drive nut 38 is mounted for vertical slidingmovement within the body member 34. The carrier 36 comprises a guide pin40 slidable in a vertical keyway 42 in the wall of the body member 34whereby to prevent rotation of the carrier 36 relative to the bodymember 34.

A substantially cylindrical vertical bore 46 extends through the carrier36. The tool holder 26 comprises a shaft portion 44 which is slidinglyreceived in a lower end portion of the bore 46 with the remainder of thetool holder 26 projecting downwardly beyond the carrier 36. A guide pin48 fixed in the shaft portion 44 is received in a slot 50 in the carrier36 whereby to prevent rotation of the tool holder 26 relative to thecarrier 36 and to restrict the distance by which the tool holder 26 maymove relative to the carrier 36 in a vertical direction. The tool holder26 is normally in a lowermost position relative to the carrier 36, withthe guide pin 48 engaging a lowermost end face of the slot 50, remainingin this position under the force of gravity: this lowermost position isa location position of the tool holder 26.

The holder 26 comprises means for interchangeably mounting one of thepick-up tools 20 with a datum face thereof positioned at a predeterminedposition relative to the tool holder. This mounting means comprises asocket 52 in a lowermost end portion of the tool holder 26 in which ashank 54 of the tool 20 is slidingly received. The tool holder 26comprises retaining means resiliently biased into a recess 56 in theshank 54 of a tool 20 received in the socket 52 to retain the tool 20 onthe holder 26. The retaining means comprises a plurality, vis. a pair,of balls 58 held captive in the holder 26 but projecting into the socket52, the balls being resiliently biased into the socket 52 by a resilientrubber sleeve 60 surrounding the lower end portion of the holder 26 andoperating on portions of the balls 58 projecting from their housing inthe holder 26 to urge the balls inwardly of the socket 52. The tool 20is accurately located at the predetermined position relative to theholder 26 by engagement of a locating face 62 of a projecting collar 64of the tool 20 with a lowermost location face of the tool holder 26,thus to locate a datum face 66 of the tool 20 relative to the holder 26so that the datum face 66 is in said predetermined position. A passage68 extends axially through the tool 20 and opens through the datum face66. An upper end portion of the passage 68 opens to means for connectingthe passage 68 to a vacuum source of the machine, said means beingprovided by a bore 70 in the tool holder 26 connected by a flexiblerubber pipe (not shown) to the vacuum source.

The machine further comprises means for moving the carrier 36, and thusthe tool holder 26, vertically between a plurality of datum positionsand further positions remote therefrom. The means for moving the carrier36 vertically comprises a lead screw 72 mounted for rotation coaxiallywith the body member 34 in bearings 74 carried by a further bracket 76of the head support member 32 and a bearing 78 at an upper end portionof the body member 34; the lead screw 72 is fixed against verticalmovement by lock nuts 80 and a circlip 82. A threaded portion of thelead screw 72 is received in the drive nut 38 so that rotation of thelead screw 72 in the drive nut 38 causes vertical movement of the drivenut (thus the carrier to which it is fixed) relative to the body member34 which is fixed against vertical movement in the bearings 28. Thus,when the tool holder 26 is at its lowermost position relative to thecarrier 36 the tool holder may be moved by rotation of the lead screw 72between a plurality of datum positions and further positions remotetherefrom.

The lead screw 72 is arranged to be driven by a servo motor 84 mountedon the head support member 32: a pulley 88 secured to an output shaft ofthe servo motor 84 drives, through a toothed drive belt 86 a pulley 90keyed to the lead screw 72. An encoder 92, also mounted on the headsupport member 32, likewise driven by the output shaft of the servomotor 84, provides a digital indication of the rotation of the outputshaft of the servo motor 84 and thus of the pulley 90 and the lead screw72 to which it is keyed: this information is used by a computer controlsytem of the machine to control the rotation of the lead screw 72whereby to control a vertical position to which the carrier 36 is moved.

As hereinbefore mentioned, the whole pick-up head 14 is rotatable in thebearings 28. A gear 94 is secured to the body member 34 of the pick-uphead 14; the gear 94 is in mesh with a gear 96 secured to the outputshaft of a stepping motor 98. As is well known stepping motors areconstructed to be rotated through a known angle each time a pulse isreceived by the motor: thus, by supply of a known number of pulses thestepping motor may be rotated through a known angle. In the case of thestepping motor 98, by causing the output shaft of the motor 98 to rotatethrough a previously determined angle by supply of the requisite numberof pulses, the body member 34 may likewise be rotated through apredetermined angle. As the carrier 36 is constrained to rotate with thebody member 34 and the tool holder 26 is likewise constrained to rotatewith the carrier 36, operation of the stepping motor 98 to rotate itthrough a predetermined angle will cause rotation of the tool holder 26through a predetermined angle, likewise. However, rotation of thecarrier 36 and thus the drive nut 38 which is secured thereto, whilstthe lead screw 72 remains fixed, will cause a change in the height ofthe carrier 36 relative to the body member 34. A clutch mechanism 100 istherefore provided which operates on a signal from a computer control ofthe machine just prior to operation of the stepping motor 98, toeffectively clamp together the lead screw 72 and the body member 34 sothat when the stepping motor 98 operates to rotate the body member, thelead screw rotates with the body member as one unit. After the steppingmotor 98 has rotated through the desired angle, the computer controlsignals release of the clutch mechanism 100 so that the lead screw 72and body member 34 can again rotate independently of one another. Theinertia provided by the stepping motor 98 together with the gears 94, 96is sufficient to maintain the body member 34 in the position to which ithas been rotated.

A bearing cap 102 is sealed in an air-tight manner to the furtherbracket 76 enclosing an upper end portion of the lead screw 72; anair-tight gasket 104 seals around the lead screw 72 towards a lowerportion of the bracket 76. A passage 106 in the bearing cap 102 allowsair under pressure to be introduced to the chamber formed between thebearing cap 102 and the bracket 76. A passage 108 extends longitudinallyalong the lead screw 72 and opens at the lower end into the bore 46 inthe carrier 36 above the upper end portion of the shaft portion 44. Alower end portion of the lead screw provides a sliding seal against thebore 46 of the carrier and likewise the shaft portion 44 provides asliding seal in the bore 46. Thus air under pressure introduced throughthe passage 106 enters the bore 46 via the passage 108 to act on theshaft portion 44 of the tool holder 26 to urge to its lowermost,location position (in which it is shown in FIG. 3). The air pressurewhich may be supplied through the passage 106 may be adjusted to apply apreselected pressure on the tool holder 26 for a reason to be discussedhereinafter.

The pick-up head 14 further comprises a plurality of, viz. two,oppositely disposed pairs of orienting jaws 110, 112 mounted formovement towards and away from a component (not shown) carried by andabutting the datum face 66 of a tool 20 mounted on the tool holder 26when the holder is in its lowermost, location position whereby to engageand orient the component. The jaws 110, 112 have a plurality ofvertically spaced sets 114, 116, 118 of cooperating datum faces whichare disposed generally transversely to the plane of the datum face 32 ofthe tool 20 in the holder 26. Each of these sets 114, 116, 118 isdisposed so as to be capable of orienting a component carried by asuitable tool 20 positioned against the tools datum face 66 of the tool,when the tool holder 26 is located in a corresponding one of the datumpositions of the holder by appropriate rotation of the lead screw 72 tomove the carrier 36 and thus the tool holder 26 to the appropriate datumposition. The tool 20 used is selected to be of most appropriateconstruction for handling the particular component in question, thedatum positions of the holder 26 being selected so that the datum face66 of the appropriate tool will be appropriately positioned verticallyso that a component abutting the particular face 66 will be in registerwith the appropriate one of the sets 114, 116, 118 of datum faces of thejaws 110, 112.

As can be seen from FIGS. 3 and 6, the jaws 110, 112 are secured in anaccurate location at lowered portions of arms 120 which are pivotallymounted by pivot pins 122 carried by parts of the body member 34. Thearms 120 mounting an opposed pair of the jaws 110, 112 are mounted forpivotal movement about horizontal, parallel axes the axes relating tothe jaws 110 being disposed at rightangles to the axes relating to thejaws 112. The arms 120 are biased outwardly by a tension spring 124 ofgenerally circular form extending around upper end portions of the arms120 in grooves 126 therein. Each pair of jaws 110, 112 may be moved insynchronism towards one another by similar means of which only the meansoperating the pair of jaws 110 will be described in detail. Each pair ofjaws may be operated independently of the other pair of jaws.

The means for moving the jaws 110 inwardly towards one another (andtowards a component carried by a tool 20 in the holder 26 when theholder is in its datum position) comprises a slide member 128 mountedfor sliding movement up and down an outer bearing portion of the bodymember 34. A pair of rollers 130 is mounted for rotation on the slidemember 128 and engage inclined upper end faces 132 of the arms 120carrying the jaws 110. Thus, when the slide member 128 is forceddownwardly, the rollers 130 slide down the inclined upper end faces 132and force the upper end portions of the arms 120 outwardly against theaction of the tension spring 124, thereby pivoting the jaws 110 inwardlytowards one another. When the slide member 128 is lifted, the rollersmove upwardly along the faces 132 thereby allowing the spring 124 tourge the upper end portions of the arms 120 inwardly, pivotting the jaws110 apart. The slide member 128 may be arranged to be raised positivelyby suitable means or may merely be lifted by action of the spring 124upon removal of downward pressure from the slide member. The slidemember 128 is arranged to be moved by means of a corresponding pistonand cylinder arrangement (not shown) carried by the head support member32 and arranged to operate on a lever 136 pivoted on the support member32. A roller 138 carried by an end portion of the lever 136 remote fromthe piston and cylinder arrangement 134 bears on a collar 140 of theslide member 128. Thus operation of the piston and cylinder arrangementpushes an end portion of the lever 136 adjacent the arrangement upwardlycausing the roller, 138 to move downwardly thereby urging the slidemember 128 downwardly and thus the jaws 110 towards one another. Meansfor operating the other pair of jaws 112 is generally similar exceptthat a slide member 142 thereof generally corresponding in function tothe slide member 128 is arranged to slide on an outer bearing surfaceprovided by the slide member 128 itself and has two recesses 144 at alower end portion thereof to accommodate the rollers 130 carried by theslidemember 128. The slidemember 142 is operated by further piston andcylinder arrangement (not shown) in similar manner to operation of theslide member 128. Thus by appropriate timing of the operation of thepiston and cylinder arrangements operation of the pairs of jaws 110, 112may be timed to occur at an appropriate moment, or indeed it is possibleto cause only one of the pairs of jaws to operate in appropriatecircumstances, for example when the component to be handled is ofcylindrical shape, in which case the component would be carried by anappropriate tool grooved to receive the cylinder and only one pair ofarms would be used operating upon opposite end portions of the cylindercomponent (a so-called "Melf" component) to both align the componentlengthwise in the tool and to orient the tool about the vertical axis oftool holder precisely (it will ordinarily have been picked up insubstantially the correct orientation when loaded into the tool holder26).

The substrate support 22 is generally of previously known constructionand comprises a so-called X-Y table having longitudinal rails 148mounted on the frame 10 on which a carriage 150 slides lengthwise of themachine, i.e. in the Y direction. The carriage 150 is arranged to bedriven along the rails 148 by means of a suitable drive mechanism 146e.g. a Rohlex drive under the control of computer means of the machine.An optical position determination system of known construction isdisposed to indicate to the computer means the precise position of thecarriage 150. Transverse rails 152 are secured on the carriage andsupport means 154 are mounted for sliding movement along the rails 152transversely of the machine, i.e. in the X direction. The support means154 is arranged to be driven along the rails 152 to and fro in the Xdirection by a suitable drive means 155 e.g. a Rohlex drive system; anoptical detection means of known construction is mounted on the carriage150 to indicate to the computer means the position of the support means154 transversely of the machine i.e. in the X direction. By operation ofthe two Rohlex drive systems, moving the support means 154 in the Xdirection and the carriage 150 (and with it the support means 154mounted thereon) in the Y direction, the support means can be movedthrough a full range of operative positions.

The support means comprises a pair of parallel rail members 156 whichare horizontal and extend in the Y direction and which provide twoupwardly facing support surfaces 158 on which pallets 160 may bemounted. Substrates 24, on which components are to be placed, aremounted on the pallets 160 for presentation to the operativeinstrumentalities of the machine in precisely known locations relativeto datum positions of the pallets 160. Each pallet has two locationholes therein at diagonally opposite corners thereon, one of the twoholes being the datum position of the pallet. The pallets 160 can belocated on the support surfaces 158 of the support means 154 in one oftwo stations--a first, adhesive dispensing station 162 or a second,placement station 164. At each of the two stations 162, 164 are disposedlocating means by which substrates can be located at the respective oneof the stations 162, 164 and clamp means by which the substrates may beclamped in the station. The locating means and clamp means at eachstation 162, 164 are identical and for convenience only those at thestation 162 will be described hereinafter. The locating means comprisestwo spaced pneumatic cylinders 166 (only one visible on drawings)secured to the support means 154 with piston rods 170 thereof arrangedto project upwardly therefrom. The cylinders 166 are mounted one on eachof the rail members, positioned to register with the location holes of apallet. When a pallet 160 is to be placed in the adhesive dispensingstation it is rested on the support surfaces 158 of the rail members 156and moved into position with the location holes substantially alignedwith the piston rods 170 which at this time are retracted within thecylinders 166; when the pallet has been placed in this position, thecylinders 166 are actuated to extend the piston rods 170 from thecylinders 166 so that conical, guiding, leading end portions of the rodsenter the holes in the pallets 160. The main body of the piston rods 170below the leading end portions is cylindrical and accurately machinedand the cylinders 166 are accurately located on the support means 154.The cylindrical portion of the piston rod 170 of the leading pneumaticcylinder 166 is arranged to slidingly engage in a circular hole (thedatum position hole) in the leading end portion of the pallet 160 andthe piston rod 170 of the trailing cylinder 166 (not visible in thedrawings) is arranged to enter an oval hole which is slightly elongatedin the Y direction (considered when the pallet is in the machine) but ofthe same width as the diameter of the leading hole. Thus the leadingcylinder 166 cooperating with the leading hole of the pallet 160 locatesthe leading end portion of the pallet and the trailing hole and thetrailing cylinder locates the pallet in angular orientation about theleading hole. The pallets 160 are of rigid construction, all of similardimensions. Datum surfaces which locate the pallets 160 in the verticaldirection (the Z direction) are provided by overhanging lips of the railmembers 156 at each of the stations 162, 164. The clamp means at eachstation 162, 164 comprise two pneumatic cylinders 168 mounted on therail members 156 positioned to register with those diagonally oppositecorners of a pallet 160 located by the locating means in which thelocating holes are not disposed. On activation of the cylinders 168(after a pallet has been located by the cylinders 166) piston rods ofthe cylinders 168 are moved into engagement with the associated cornersto raise the upper surface of the pallet into engagement with and clampthe pallet against the datum surfaces of the lips; thus, an uppersurface of the pallet is located accurately in the Z direction so thatthe height in the Z direction at which components are to be placed canbe included in the information supplied to the computer means.

The pallets 160 may support one or several printed circuit boards inknown positions relative to the datum point of the pallet; should theboard on which components are to be placed already carry any componentor other structure projecting below a lower surface of the substrate,appropriate openings may be made in the pallet 160 to accommodate theprojecting portions. Alternatively the substrate 24 may, itself, be aprinted circuit board of suitable dimensions, provided that the board issufficiently rigid, in which it is not necessary to use a pallet.

The machine embodying the invention described herein comprises twopick-up heads 14 as hereinbefore mentioned, the heads being mounted onthe head support member 32 which itself is mounted for sliding movementtransversely of the machine (in the X direction) on the bridge member 12of the frame 10, above the substrate support 22. The head support member32 is mounted for sliding movement on a rail system 174 secured to thebridge member 12: wheels 176 mounted for rotation on the head supportmember 32 run on the rail system 174 whereby to permit the said slidingmovement. The head support member 32 is moved along the rail system 174by a Servo motor which rotates a shaft 178 mounted for rotation on thebridge member 12 and drives the head support member 32 through a Rohlexdrive mechanism. The position of the head support member 32 transverselyof the machine (in the X direction) and thus of the pick-up heads 14carried by the member 32 is verified by an optical encoder system (notshown).

As hereinbefore mentioned the carriages 16 on which component supplymagazines 180 and the tool supports 18 are carried are mounted one ateither side of the substrate support 22. Each of the carriages 16 ismounted for sliding movement (in the Y direction) on rails 182, thecarriages being arranged to be moved by shafts 183 driven by motors,through Rohlex drive mechanisms. Suitable rotary encoders driven bytoothed belts on the carriages, are associated with each carriage toindicate the precise position of the carriage 16 in the Y direction ofthe machine to the computer means. Each of the carriages 16 mounts aplurality of component supply magazines 180 of known type, for exampletape feed magazines in which sticks are carried in pockets in a reeledtape, so-called "stick" feed magazines or vibrating trough feeders. Eachcarriage 16 may be moved on the rails 182 to present a component at anoutlet position of any selected one of the magazines 180 mounted on thecarriage 16 at a pick-up position associated with one of the pick-upheads 14. By movement of the head support member 32 along the bridgemember 12 one of the heads 14 associated with one of the pick-uppositions may be moved between a placement position 186 (in which thehead is arranged to place a component upon a substrate carried on thesubstrate support) and a position remote from the placement positionadjacent the associated pick-up position to pick-up componentstherefrom. As discussed previously, tools carried by each of the pick-upheads 14 can be moved vertically in the Z direction, by operation of thelead screw 72, both to pick-up components at the pick-up position and toplace components on a substrate when the appropriate head 14 is in theplacement position 186. The two heads 14 are mounted side by side,spaced apart in the X direction by a distance such that when one of theheads 14 is in the placement position 186, the other of the heads isdisposed in register with its associated pick-up position: thus when thetool holder 26 of a head 14 in the placement position 186 descends toplace a component on a circuit board carried by a pallet 160 located atthe placement station 164, the holder 26 of the head 14 in register withits associated pick-up position may also descend to pick-up a componentfrom the outlet of a magazine 180 disposed at the pick-up position.Having respectively placed and picked-up components the two tool holders26 may be raised and the head support member 32 moved in the X directionto bring the one of the heads 14 now carrying a component to theplacement position 186 and to move the other head 14 above itsassociated pick-up position to pick-up a further component forsubsequent placement. It will be realized that each head 14 moves toprecisely the same placement position 186 to place its component. Thesubstrate support 22 is moved by the X-Y table arrangement so that anypreselected point in the work area of a pallet substrate 24 mounted inthe placement station 164 can be moved into register with the head inthe placement position 186.

As has been mentioned previously, a tool support 18 for an associatedpick-up head 14 is carried on the appropriate one of the two carriages16: the tool supports are both mounted at intermediate positions abouthalfway along the carriage 16. Each tool support 18 comprises a base 188secured to the carriage 16 and slide member 190 mounted for slidingmovement on an upper surface of the base 188. The slide member 190 isretained on the base 188 by headed pins 192, the pins passing throughslots 194 in the slide member, 190 whereby to guide the slide member 190for sliding movement in the X direction. The slide member 190 can bemoved in the X direction by a piston and cylinder arrangement 196mounted on the frame 10, through a linkage mounted on the carriages 16to the extent permitted by the headed pins 192 in the slots 194.

The linkage comprises a two arm lever 197 pivotally mounted on thecarriage 16 and so positioned that when the carriage is so positioned onthe rail 182 that the tool support 18 is at a tool-loading position,corresponding with the pick-up position of the magazines 180, one arm ofthe lever is aligned with a piston rod 198 of the piston and cylinderarrangement 196. The other arm of the lever 197 is pivotally connectedto one end portion of a link 199 the other end portion of which ispivotally connected to one end portion of a lever 201 pivotally mountedon the carriage remote from the arrangement 196. The other end portionof the lever 201 is pivotally connected to a connecting rod 203, itselfpivotally connected to a bracket depending from the slide member 190. Aspring 207 round the connecting rod 203 is interposed between a collar205 fixed to the rod and a guide 209 for the rod 203 fixed to the base188. The spring 207 urges the slide member to the left (viewing FIGS. 4and 5). When the tool support 18 is at the pick-up position and thepiston and cylinder arrangement 196 is operated to extend the piston rod198 into engagement with said one arm of the lever 197 whereby to movethe lever 197, the linkage arrangement causes the slide member 190 tomove to the right viewing FIG. 4 to the position in which it is shown inFIG. 4, compressing the spring 207; when the piston rod 198 is retractedthe spring 207 returns the slide member 190 to the left from theposition in which it is shown in FIGS. 4 and 5.

A plurality of cylindrical recesses 200 are formed in the base 188,having their centres spaced along a line lying in the X direction. Therecesses 200 are dimensioned to receive a nose 202 which projects fromthe collar 64 of a tool 20 at the opposite side of the collar 64 to theshank 54. Additionally the uppermost surface of the base 188 is recessedto accommodate the collar 64 of the tool 20. The slide member 190 has aslot 204 therein extending in the X direction, the slot 204 beingsufficiently wide at all parts to permit the shanks 54 of tools 20accommodated in the recesses 200, to project upwardly through the slot204. The slot 204 has enlarged portions 206 which are so dimensioned asto allow clearance for the tool 20 to be withdrawn from the recesses 200through the enlarged portions 206 when the enlarged portions are alignedwith the recesses 200. However when the slide member 190 is moved sothat the enlarged portions 206 and recesses 200 are not in register,portions of the slide member 190 overlie the collars 64 of tools 20received in the recesses 200 thereby retaining the tools 20 in therecesses.

The tool support 18 therefore comprises a housing, provided by the base188, by which tools are supported in a plurality of positions, viz. inthe recesses 200, with their shanks 54 projecting. The means for movingthe tool holders 26 which includes means for moving the pick-up heads14, and for moving the carriages 16 provide means for relatively movingthe tool holders 26 and tool support 18 which are effective in theoperation of the machine to engage the shank 54 of one of the tools 20from a preselected one of the recesses 200 in the socket 52 of the toolholder 26 thus to mount the preselected tool in the holder. By movingthe carriage 16 carrying the tool support 18 along a first path (in theY direction) and by moving the associated one of the pick-up heads 14along a second path, viz. in the X direction, at rightangles to thefirst path, the tool holder 26 may be aligned with a preselected one ofthe recesses 200 of the tool support 18. When so aligned, movement ofthe tool holder 26 by operation of the lead screw 72, in the Z directioncan move the holder 26 into engagement with the preselected one of thetools 20 carried in the preselected recess 200 whereby to mount the tool20 in the holder 26, or, where a tool is to be deposited from the holder26, move the holder 26 to place the tool 20 in the preselected recess.When a new tool 20 is to be picked up by the tool holder 26 (a previoustool having been removed) it will be necessary to move the slide member190 by operation of the piston and cylinder arrangement to align theenlarged portions 206 with the recesses 200 (as shown in FIG. 4) so thata leading end portion of the tool holder 26 can be pushed over the shank54 with the shank 54 received in the socket 52 until the lowermost faceof the holder 26 engages the locating face 62 of the collar 64 and theballs 58 engage the recess 56 in the shank 54. When it is desired tounload a tool 20 from the holder 26, the holder 26 is first aligned bymoving the appropriate pick-up head 14 in the X direction and thecorresponding carriage 16 in the Y direction, with the particular one ofthe recesses 200 designated for the particular tool 20 to be unloaded.The slide member 190 is moved to align the enlarged portions 206 withthe recesses 200 and the tool holder 26 is lowered to place theparticular tool 20 in its appropriate recess. With the tool holder 26still lowered the pressure is removed from the piston and cylinderarrangement 196 and the slide member 190 is returned by action of thespring 207 so that the enlarged portions 206 are moved out of alignmentwith the recesses 200 and portions of the member 190 slide over thecollars 64. The holder 26 is then raised and the balls 58 leave therecess 56, being forced outwardly of the socket 52 against the resilientbiasing provided by the rubber sleeve 60: means (not shown) may beprovided to assist separation of the tool from the holder in addition tothe action described above, if necessary. From the above it will beappreciated that various tools 20 carried by the tool support 18 may beinterchanged for one another during a cycle of operation of the machine,provided that the machine is programmed to carryout the necessarymovements. In order to pick-up a tool from or return a tool 20 to itsappropriate recess 200 it is necessary to move the head into alignmentwith the appropriate recess 200. As the recesses 200 are spaced apart inthe X direction, the one of the pick up heads not aligned with the toolsupport 18 will be disposed above the substrate support but not normallyat the placement position 186 as most of the recesses will not besuitably positioned to permit this. Thus when a tool change is takingplace, the pick-up head 14 not involved in the change will remain idle.

The piston and cylinder arrangement 196 is also arranged to operate thecomponent supply magazines 180. For example, in order to feed acomponent in a tape feeder magazine to the outlet position of themagazine it is necessary to index the tape forward by the distancebetween adjacent components: a feed system, comprising a linkage on themagazine is arranged to do this. The linkage is so constructed that whena magazine 180 is positioned by movement of the carriage on which it issupported in the pick-up position an actuating lever of the linkage ispositioned in register with the piston rod 198 of the piston andcylinder arrangement 196. The arrangement 196 is operated under controlof the computer means at the appropriate time in the operation of themachine to index the component supply tape through one feed step thus tomove a component to the outlet of the magazine for picking up by theassociated pick-up head.

An adhesive dispenser 208 is mounted on the bridge member 12, at theopposite side to the head support member 32, above the adhesivedispensing station 162. The adhesive dispenser 208 is mounted formovement vertically, in the Z direction, but cannot move in the X or Ydirections. The adhesive dispenser comprises a container of knownconstruction in which a quantity of a suitable adhesive, for example anepoxy adhesive is contained. The dispenser 208 is arranged so that dropsof adhesive may be expelled from a nozzle thereof by pneumaticoperation, in known manner. The adhesive dispenser 208 can be used toapply adhesive to a substrate mounted on the support 22 in the adhesivedispensing station 162 at any desired position in the work area of theadhesive dispensing station 162, the X-Y table of the substrate support22 being operated to move the appropriate point on the substrate 24 intoregister with the adhesive dispenser 208. The adhesive dispensingstation 162 and placement station 164, and the adhesive dispenser 208and placement position 186 are disposed in relation to one another suchthat a pick-up head 14 at the placement position 186 places a componenton the same position on the work area of a pallet 160 mounted in theplacement station 164 on the substrate support 22, as the adhesivedispenser 208 places a drop of adhesive on the work area of a pallet 160carried by the support 22 in the adhesive dispensing station 162. Thusif both of the pallets 160 at the adhesive dispensing station 162 andthe placement station 164 carry an identical array of substrates 24 theplacement head 14 at the placement position 186 places its component atthe same position on a substrate in the station 164 as a drop ofadhesive is placed on the corresponding substrate at the station 162. Toachieve the necessary register between the positions in this case itwill be necessary to mvoe the X-Y table only to one position and then toactivate a head at the placement position 186 and the adhesive dispenser208 simultaneously, thereby improving the throughput rate of themachine. When all of the electrical components have been placed onsubstrates 24 carried by a pallet 160 in the placement station 164 thepallet 160 is removed and replaced by a pallet 160 which had previouslybeen disposed in the adhesive dispensing position 162 and on whichadhesive was placed by the dispenser 208 as the components were placedon the preceding pallet at the placement position 164.

The tool holders 26 further comprise a detector which detects whether ornot a tool 20 is present on the holder 26 when a component is to bepicked up during the operation of the machine. Detector means (notshown) are also associated with the vacuum supply to the passage 68which can detect whether or not a tool 20 in the holder 26 has succeededin picking up a component at the pick-up position; other forms ofdetector for checking whether or not components have successfully beenpicked up (and placed on a substrate) may be used if desired instead ofthe detector means in the vacuum system referred to above.

As hereinbefore mentioned the operation of the machine is controlled bya suitable electronic computer control system which is programmed by anoperator, conveniently by a so-called "walk through" method in which themachine is moved at a slow rate by the operator to perform the necessarysequence of operations which are recorded in a memory for subsequentrepetition. Before starting the machine operation it is necessary tofirst ensure that appropriate tools 20 are accommodated on the toolsupport 18 on both of the carriages 16 and that the magazines 180 onboth carriages contain sufficient of the correct components needed forthe assembly operation proposed. Suitable substrates 24 are firstmounted in known locations on appropriate pallets and a pallet carryingthe substrates mounted on the substrate support 22 in the adhesivedispensing station 162 as described above. The X-Y table is thenoperated to move the pallet 160 in the adhesive dispensing station 162to align the adhesive dispenser 208 with positions on the work area ofthe pallet at which adhesive is to be placed and spots of adhesive aredispensed at the preselected positions on the substrates carried by thepallet. The pallet 160 is then moved from the adhesive dispensingstation 162 to the placement station 164 by the operator, at whichstation the pallet is located; further pallet 160 on which are alsomounted substrates 24 in positions corresponding identically with thoseon the first pallet is then positioned at the adhesive dispensingstation 162. The X-Y table is again operated to bring the adhesivedispenser 208 into register with the various preselected positions onthe substrates carried by the pallet at the dispensing station 162 andthe placement position 186 into register with the correspondingpositions on the substrates 24 carried by the pallet 160 at theplacement station 164. At each of the preselected positions a drop ofadhesive will be placed on the substrate in register with the adhesivedispenser 208 and/or a component will be placed on the correspondingsubstrate at the placement station 164. The control system of themachine is organised so that the appropriate one of the pick-up heads 14picks up the necessary component from its associated supply of componentsupply magazines 180 carried by its associated carriage 16 and has thenecessary component available at the placement position 186 whenrequired for placement. In order to handle the necessary components itwill be necessary to ensure that the tool holder 26 of the appropriatepick-up head 14 is provided with a tool 20 suitbale to handle therequired component and it will therefore be necessary to interchangetools carried by the tool support 18 to achieve this. The sequence ofmovement is arranged to ensure placing of spots of adhesive and pickingand placing of components using the correct tools for the variouscomponents in the most efficient manner. As will be recalled the toolholder 26 is urged downwardly by air under pressure admitted to the bore46. The pressure of air in the bore 46 is selected to ensure that anadequate downward pressure is applied to a component placed on asubstrate by the pick-up head 14 to ensure good bonding to thesubstrate, while not exerting sufficient pressure to cause any damage tothe component. In order to ensure that the components are positioned inthe necessary position and in the correct orientation the control meansof the machine is arranged to operate the stepping motor 98 after acomponent has been picked-up and oriented by the jaws 110, 112, torotate the component to the necessary orientation at which it isdeposited on the substrate. An optical system supplies a confirmation tothe machine when rotation of a component through intervals of 90 degreeshas been achieved.

A flow control means, adjustable by the operator before the machine isstarted to the most appropriate level, is provided to control the inwardspeed of the jaws 110, 112 (by controlling flow of air to the piston andcylinder arrangements 134, 146). The inward speed of the jaws ispreferably set to be as rapid as possible to ensure the most rapidmachine cycle time, without risking dislodging components which are heldon the tool by vacuum: too rapid an inward movement of the jaw maydislodge components. When a component has been picked from the pick-upposition by a tool 20 in the tool holder 26 as aforesaid, the toolholder 26 is raised by a suitable amount under the control of the Servomotor 84 associated therewith until the holder is in the appropriate oneof its datum positions, with the component aligned with the appropriateset of jaws 114, 116, 118. As the tool holder 26 approaches theappropriate datum position the piston and cylinder arrangements areoperated (according to the programming of the machine) to pivot the arms120 inwardly, as discussed above, so that as the tool holder 26 reachesthe appropriate datum position the component carried by the tool 20 isengaged by the appropriate ones of the pairs of jaws 110, 112. The tool20 in the holder 26 will have been selected from the tool support 18 tobe appropriate for the dimensions of the component to be picked up andthe datum position to which the tool holder is moved will ensure thatthis appropriate tool, the component is positioned correctly in relationto the sets of orienting faces 114, 116, 118. The datum faces 114 areintended to orient the smallest ccmponents, the faces 116 to orientintermediate sized components and the faces 118 to orient the largestccmponents which can be handled by the machine. In FIG. 7 the jaws 110,112 are shown handling a larger component, a so-called S.O. component213, with leads 214 projecting from the two, opposite, longest sides. Inorder to make the necessary electrical connections it is essential thatthese leads are located correctly. The sets 116, 118 of datum faces areshaped to achieve this by providing a recess 210 in the datum faces ofthe end jaws 110 of the sets 116, 118. As can be seen from FIG. 7, anend portion of the body of the component is received in this recess andthe datum faces engage the leads themselves so that orienting isachieved by contacting the leads 214; likewise the set 118 of datumfaces of the pair side jaws 112 contact the leads 214. As can be seenfrom FIGS. 7 and 9 the set 118 of datum faces of the side jaws 112 isslightly angled: the angle is chosen to effect a slight camming actionof components contacted by the datum faces 118 of the jaws 112 upwardlytowards the tool holder 26 so that the components are pressed firmlyagainst the tool 20 thereby ensuring that when the jaws 110, 112 areopened, the components are maintained in the correct location. As theside jaws 112 are closed against the component slightly before the endjaws 110, this camming action takes place before engagement of the endjaws 110 with the component. The smallest set of orientation faces 114is used primarily for orienting so-called "chips", small capacitors andresistors. Operation of the jaws is controlled so that the jaws 110engage the component to be oriented slightly before the jaws 112.Engagement of the component by the appropriate set 114, 116, 118 causesthe component to be correctly oriented and positioned on the tool 20. Asthe jaws orient the component on the end of the tool 20 the head supportmember 32 is moved in the X direction to carry the head 14 from abovethe pick-up position to position the head 14 at the placement position186 whilst at the same time the substrate support 22 is positioning aparticular locus of a substrate carried on a pallet 160 in the placementstation 164 in register with the placement position 186. When both thesubstrate 24 and the appropriate head 14 are positioned in the desiredpositions so that the head 14 is in register with a predeterminedposition on the substrate 24, the piston and cylinder arrangements areoperated to open the jaws 110, 112 thus to release a component, thecomponent being maintained in position on the tool by vacuum appliedthrough the passage 68. The carrier 36 and tool holder 26 are thenlowered by the Servo motor 84 and lead screw 72 to a position in whichthe component is placed on the substrate: the level to which the carrier36 descends will depend on the thickness of the component to be placedand on the substrate 24 but the carrier 36 normally will descend to thesame position relative to the substrate 24, any variation in thicknessbeing accommodated by movement of the holder 26 relative to the carrier36 against the air pressure in the bore 46. However for very thickcomponents the lead screw operation will be controlled to ensure thatthe tool holder 26 does not descend too far. The component will bepressed against the predetermined position on the substrate under apreselected pressure determined by the air pressure in the bore 46 andheld in that position for a short time until the tool holder 26 israised. The selected pressure is such as to ensure adequate adhesion ofthe component in the predetermined position without significantlikelihood of damage to the component. If necessary during transport ofthe pick-head 14 from above the pick-up position to the placementposition 186 in its X direction, rotation of the head by the motor 98will have taken place as hereinbefore mentioned.

After the component has been placed in the desired position on thesubstrate 24 and the tool is to be raised leaving behind the componentit must be ensured that the component remains on the substrate 24 anddoes not adhere to the tool 20. To ensure separation of the tool 20 fromthe component a positive air pressure may be introduced into the passage68, instead of the vacuum, this being necessary where large componentsare being placed as the tools used in placing larger components tend tonot separate readily from the components. In any event, if no positivepressure is used, the vacuum in the passage 68 must be reduced toatmospheric pressure to permit separation: where smaller components areto be placed, use of a positive pressure in the passage 68 may displacethe components from the desired position on the substrate and thereforein this instance atmospheric pressure in the passage 68 is preferred.

The noses 202 of the tools 20 are shaped according to the componentswhich they are intended to handle, the larger components being arrangedto be handled by tools having noses with a larger datum face 66 than thesmaller components. In FIG. 3 the tool shown is particularly appropriatefor handling the smaller sized components. The length of the nose 202projecting beyond the collar 64 to the datum face 66 together with thedatum position to which the tool holder 26 is moved by the lead screw 72will determine which of the sets of datum faces 114, 116, 118 willengage a component carried by the tool when the arms 120 are pivoted tomove the jaws 110, 112 inwardly.

From the foregoing it will be seen that the pick-up head of the machinedescribed herein can handle wide range of component sizes withoutinterference by the operator during operation of the machine in aplacement operation, the jaws 110, 112 together with the appropriatetools being capable of orienting components of a wide variety ofdimensions.

Although the machine has been described hereinbefore in its use inplacing components on spots of adhesive applied by the dispenser 208,the components may be placed at the station 164 on adhesive depositssupplied prevously. Likewise adhesive may be applied in the machine foruse in subsequent operations.

As previously mentioned the machine may handle cylindrical components:in this case the tool used will have a nose terminating in a recesscomplementary with the cylindrical component to be handled and any onepair of jaws will be used to locate the component accurately on thetool, the recess being operative to position a component in cooperationwith the single pair of jaws. This system will apply to so-called "Melf"components.

I claim:
 1. A head for handling electrical components comprising a toolholder, means for moving the holder between a plurality of datumpositions and further positions remote therefrom, the holder havingmeans for interchangeably mounting a tool with a datum face thereofpositioned at a predetermined position relative to the tool holder, thehead further comprising a plurality of orienting jaws mounted formovement towards and away from a component carried by and abutting thedatum face of a tool mounted on the tool holder when the holder is inone of the datum positions whereby to engage and orient a componentcarried by the tool, the jaws having a plurality of spaced sets ofcooperating datum faces generally transverse to the plane of the datumface of a tool in the holder, each set of datum faces of the jaws beingso disposed as to be capable of orienting a component carried by a toolmounted on the tool holder when the holder is at a corresponding one ofsaid datum positions.
 2. A head according to claim 1 in which the meansfor moving the tool holder is mounted on a housing of the head to movethe holder vertically between its datum positions and said positionsremote therefrom and the sets of datum faces of the jaws are disposed tocooperate with a tool having its datum face located in a correspondingone of vertically spaced predetermined positions, each corresponding toone of the datum positions of the holder.
 3. A head according to claim 2in which the jaws are carried by arms pivotted on the housing.
 4. A headaccording to claim 1 in which each set of datum faces of the jaws isconstructed and arranged for operation on components within a range ofdimensions.
 5. A head according to any one of the preceding claims inwhich the tool holder has a socket in which a shank portion of a toolcan be received to mount a tool on the holder.
 6. A head according toclaim 5 in which the tool holder comprises retaining means which isresiliently biased into a recess in the shank of a tool received in thesocket whereby to retain the tool on the holder.
 7. A head according toclaim 6 in which the retaining means comprises a plurality of balls heldcaptive in the holder but projecting into the socket, the balls engagingin a recess in the shank to retain the tool on the holder.
 8. A headaccording to claim 5 comprising a locating face against which a locatingface of a tool abuts when a tool is mounted on the holder whereby tolocate the datum face of the tool relative to the holder so that thedatum face of the tool is at said predetermined position.
 9. A headaccording to claim 1 in which the means for moving the tool holdercomprises a lead screw driven by a motor.
 10. A machine for handlingelectrical components comprising a head according to claim 1, a toolsupport for supporting a plurality of tools and means for relativelymoving the head and tool support whereby to mount a preselected toolcarried by the tool support on the tool holder.
 11. A machine accordingto claim 10 so constructed and arranged as to deposit a first tool fromthe tool holder in a preselected position of the tool support and thento mount a second tool from a second preselected position of the toolsupport on the tool holder.
 12. A machine comprising a head according toclaim 5 comprising a tool support for supporting a plurality of toolsand means for relatively moving the head and tool support whereby tomount a preselected tool carried by the tool support on the tool holderin which the tool support comprises a housing by which tools aresupported in a plurality of positions with their shanks projecting andthe means for relatively moving the head and tool support is effectivein the operation of the machine to engage the shank of a tool in apreselected one of the positions in the socket of the tool holderwhereby to mount a preselected tool in the holder.
 13. A machineaccording to claim 12 in which the tool support comprises means forengaging a tool carried by the tool holder, separating it from theholder and depositing it in a preselected position of the tool support.14. A machine according to any one of claims 10 to 13 comprising meansfor moving the tool support along a first path and means for moving thehead along a second path at right angles to the first path to align thetool holder with a preselected one of the tools carried by the toolsupport and means for moving the tool holder when so-aligned intoengagement with the preselected tool whereby to mount the tool in theholder.
 15. A machine according to any one of claims 10 to .[.14.]..Iadd.13 .Iaddend.comprising means for supplying components to the head,a support for a substrate on which components are to be placed, andmeans for effecting relative movement between the support and the headwhereby to ensure that the head is in register with a predeterminedposition at which a component is to be placed.
 16. A machine forhandling electrical components comprising a head according to claim 1, asupport for a substrate on which components are to be placed a carriagemounting a plurality of component magazines and a tool support, meansfor moving the substrate support along a first path and a second path atrightangles to the first, means for moving the carriage along a pathparallel with said first path whereby to present a component at anoutlet position of a preselected one of the magazines at a pick-upposition or to present the tool support in its tool-loading position,and means for moving the head along a path at rightangles to the firstpath between a placement position at which the head is aligned bymovement of its substrate support with a predetermined position of a ofthe substrate, a preselected position on the tool support which has beenmoved into its tool-loading position by the carriage, or with thepick-up position, whereby to place a component on the substrate at saidpredetermined position, to deposite a tool on, or mount a tool from,said preselected position on said tool support, or to pick-up acomponent at the pick-up position respectively.
 17. A machine accordingto any one of claims 10 to 13 .Iadd.or 16 .Iaddend.comprising means forconnecting a passage opening through the datum face of a tool mounted inthe tool holder to vacuum.
 18. A machine according to any one of claims10 to .[.17.]. .Iadd.13 or 16 .Iaddend.comprising means for rotating thetool holder of a head through a predetermined angle.
 19. A head forhandling electrical components comprising two pairs of opposed jaws,each jaw having a plurality of orienting faces, the orienting faces ofeach jaw being disposed to cooperate with corresponding orienting facesof the other jaws of the head providing a plurality of sets of orientingfaces as the pairs of jaws are moved towards one another in theoperation of the head, .Iadd.means for moving each pair of jaws indirections perpendicular to each other to engage .Iaddend.a componentbetween the jaws .[.being engaged.]. by the orienting faces of .Iadd.atleast .Iaddend.one of the sets as the jaws of each pair are movedtowards one another whereby to orient the components in a preselectedorientation.
 20. A head according to claim 19 in which the jaws of onepair are constructed to interengage between the jaws of the other pairas the jaws of each pair are moved towards one another.
 21. A headaccording to either one of claims 19 and 20 wherein a recess to receivea body portion of a component is provided in the datum faces of at leastone set of datum faces of one pair of jaws so that the datum facesengage leads of the component.
 22. A head according to any one of claims19 .[.to 21.]. .Iadd.and 20 .Iaddend.wherein the datum faces of at leastone set of faces, on at least one pair of jaws are inclined whereby toprovide a camming action as the jaws are closed on a component urgingthe component into engagement with a tool holder of the head.
 23. A.[.set of jaws for a.]. head according to claim .[.18.]. .Iadd.19wherein .Iaddend.each jaw .[.having.]. .Iadd.within a pair of jaws has.Iaddend.a plurality of orienting faces, each orienting face beingarranged to cooperate with corresponding orienting faces of other jawswhereby to provide a plurality of sets of orienting faces.